BODIPYs with Chalcogenophenes at Boron: Synthesis and Properties.

Area of Science:

• Organic Chemistry
• Materials Science
• Photochemistry

Background:

• Boron-dipyrromethene (BODIPY) dyes are widely used due to their tunable photophysical properties.
• Functionalization of the BODIPY core can significantly alter their performance for specific applications.
• Incorporating heterocycles at the boron atom offers a novel approach to modify BODIPY characteristics.

Purpose of the Study:

• To synthesize and characterize a new series of BODIPY dyes functionalized with chalcogenophenes at the boron center.
• To investigate the impact of different heterocycles on the photophysical and structural properties of BODIPY dyes.
• To explore the relationship between heterocycle mass and singlet oxygen generation via the heavy atom effect.

Main Methods:

• Synthesis of BODIPY derivatives through nucleophilic attack of lithiated chalcogenophenes on a parent F-BODIPY.
• Characterization of synthesized compounds using spectroscopic techniques (e.g., NMR, UV-Vis, fluorescence).
• Photophysical measurements including singlet oxygen quantum yield (ΦΔ) and fluorescence quantum yield (Φf) determination.

Main Results:

• Successful synthesis of BODIPYs incorporating furan, thiophene, selenophene, and tellurophene at the boron atom.
• Demonstration of the heavy atom effect, where increasing heterocycle mass correlates with higher singlet oxygen quantum yields.
• The tellurophene-substituted BODIPY exhibited the highest singlet oxygen quantum yield (ΦΔ = 0.68) and significantly reduced fluorescence emission (Φf = 0.01).

Conclusions:

• The strategic placement of chalcogenophenes at the boron atom provides a versatile route for tuning BODIPY photophysical properties.
• The heavy atom effect is a key factor in enhancing singlet oxygen generation in this series of BODIPY dyes.
• Tellurophene-BODIPY shows promise for applications requiring efficient photosensitization, such as photodynamic therapy.